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[Root Pointer] New Documentation
by Phil Bouchard 15 Apr '16

15 Apr '16

Greetings, - I beefed up the tutorial in the following documentation and now it covers everything I know about it: http://philippeb8.github.io/root_ptr/ - As some of you already know I added a performance comparison chart in the introduction: http://philippeb8.github.io/root_ptr/root_ptr/intro.html - I fixed the deadlinks - I added a cast operation helper in the root_ptr class: https://github.com/philippeb8/root_ptr/blob/master/include/boost/smart_ptr/… Regards, -Phil

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[variant] address of a variant type from the address of its sub-object?
by Andrzej Krzemienski 15 Apr '16

15 Apr '16

Hi, Is there a portable way (guaranteed by the interface) to do the following? I have an object 'ob' of type Ob and know its address. I know it is an active sub-object of a variant type, where Ob is one of the sub-types. Is there a way to compute the address of the containing variant object? The problem I am solving is to how to access the whole variant object from inside a static visitor: ``` using VariantOb = boost::variant<Ob>; struct MyVisitor : boost::static_visitor<> { void operator()(Ob const& ob) const { // --> get the address of the variant object ? boost::addressof(ob) + what_offset; ?? } }; ``` Regards, &rzej

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Invoking a library's build//stage ignores --stagedir?
by Peter Dimov 14 Apr '16

14 Apr '16

Let's suppose that for some random reason I want to stage Boost.System into c:\stage with the current directory being outside the Boost root, which is at c:\projects\boost-git\boost: C:\Users\Peter Dimov>b2 -sBOOST_ROOT=c:\projects\boost-git\boost --stagedir=c:\stage c:/projects/boost-git/boost/libs/system/build//stage This doesn't work. Or rather, it works, but stages into C:\projects\boost-git\boost\libs\system\stage, ignoring the --stagedir. I have no idea why. I tried to debug with -d+7, and BOOST_STAGE_LOCATE is set correctly from --stagedir, but then Boost.System is staged to its local stage directory. Does anyone have an idea what's wrong here?

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[multiprecision] Bug in double to cpp_bin_float conversion?
by Rob Conde 14 Apr '16

14 Apr '16

Consider the following code: #include <boost/multiprecision/cpp_bin_float.hpp> #include <iostream> int main() { typedef boost::multiprecision::cpp_bin_float_quad float128_t; float128_t f1(1e-9); float128_t f2("1e-9"); std::cout << std::setprecision(std::numeric_limits<float128_t>::max_digits10); std::cout << f1 << std::endl; std::cout << f2 << std::endl; return 0; } I'm getting as output: 1.000000000000000062281591457779856419e-09 9.999999999999999999999999999999999325e-10 The conversion of the double literal is not as expected. On wand box: http://melpon.org/wandbox/permlink/uSGNQZAEEytmb3ao Is this a bug? If not, what would be the correct way to get my expected behavior? Thanks, Rob Conde

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[metaparse] how do I log a boost ticket?
by Aparna Kumta 13 Apr '16

13 Apr '16

I want to submit a Boost ticket at https://svn.boost.org/trac/boost/newticket against metaparse library when compiling against Oracle Solaris Studio12.5. However, I do not see 'metaparse' under the 'Component' tab. Should I be logging a bug elsewhere? I have gone ahead and submitted a PR. https://github.com/boostorg/metaparse/pull/6. Thanks, Aparna

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Serialize a an image with Boost & GIL
by Visual Designer - Digital Team 13 Apr '16

13 Apr '16

Hi, I'm currently using boost serialization in order to save/load my data structure. The problem is that it contains some images and even with the ZIP compression the files are really big (4x bigger than the jpeg). So, I'm looking for a way to compress a RGB/A image (HDR or not) (without file operation) in memory. If possible without using any image compression library, we already use OpenImageIO but it is not possible for now ! Any idea ? I have found the GIL library, but can't find how to: 1) convert raw to GIL image 2) serialize the GIL image 1) deserialize the GIL image 2) convert the GIL to raw image Of course, the goal is to have a good compression without writing temporary file ! Thanks --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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[endian] Some suggestions
by Tatsuyuki Ishi 13 Apr '16

13 Apr '16

Mr. Beman, Here are some suggestions for the endian library. 1. Bring back float: make a proper reason for abandon You told about NaN: but it shouldn't apply since you store it in char buffer. Provide a proper reason: float is still needed since this is the only library that wraps details (platform endianness detection+compiler builtin optimizations). Float points are indispensable in data formats. I have to do a reinterpret_cast now as a workaround. 2. Remove n_bits(endian buffers): completely useless This just look like an alternative to sizeof, and always /8'd when used. What's the meaning of that? 3. Minor API suggestions Move operator type to endian_buffer: it's not related to arithmetic but just used because it can act like an integer. Non-const data(): I'm tired to do reinterpret_cast. Look at C++11 vector for a reference. Move stream operators to endian_arithmetic: I first thought that was for reading binary. That's basically unused.

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Re: [boost] [endian] Some suggestions
by Tatsuyuki Ishi 13 Apr '16

13 Apr '16

> > 1. Bring back float: make a proper reason for abandon > > You told about NaN: but it shouldn't apply since you store it in char > > buffer. > > > > The problem isn't when storing into the char buffer, but later on a > different machine or compiler when the char buffer has to be converted to a > float type. I know nothing other than float format differences, and my target platforms are using iec559. I think reinterpret_cast should work: char data shouldn't be changed as long as stored as char. > > In testing, I even ran into a case were on the same machine and compiler > the float data failed to round-trip correctly if the program that created > the file was compiled with a different set of optimization options that the > program the read the file. > I will be happy if you provide some example. > > > > > 2. Remove n_bits(endian buffers): completely useless > > This just look like an alternative to sizeof, and always /8'd when used. > > What's the meaning of that? > > > > Please give a specific code example from the docs of what you think should > be changed. Or submit a pull request. > Since this is breaking API, I'd like you to make the decision to change it or not. For detail, this is the endian_buffer definition: template <order Order, class T, std::size_t n_bits, align A = align::no> class endian_buffer; n_bits looks quite useless here. It's basically sizeof*8. > > > > > 3. Minor API suggestions > > Move operator type to endian_buffer: it's not related to arithmetic but > > just used because it can act like an integer. > > > > Again, what code is it you think should be changed? Operator value_type()? > Please submit a pull request. > Exactly: operator value_type(). This will provide much more convenience. An example: when you specify the size for the array: endian_buffer size; dynarray d(size.value()); vs dynarray d(size); > > > Non-const data(): I'm tired to do reinterpret_cast. Look at C++11 vector > > for a reference. > > > > What is the motivation? What are the safety implications? What are the > alternatives? The C++11 (and also C++17) addition of non-cost data() > members to some standard library containers was supported by motivation and > safety analysis. > Seems endian_buffer is targeted for using in structs. Then is there any problem to provide a wrap of reinterpret_cast? At least, it should be safe by design. > > > Move stream operators to endian_arithmetic: I first thought that was for > > reading binary. That's basically unused. > > > > I must be missing something. Why wouldn't stream operators apply to endian > buffers? A code example might help. > Quite confusing. I first thought that was binary r/w operators that reads/writes the stream and store the value. The problem is that, there's no method provided for reading from binary, so this is also a reason for the previous data() suggestion.

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[iostreams] Maintainer not working
by Tatsuyuki Ishi 13 Apr '16

13 Apr '16

Seems nobody is doing code review for iostreams since February. Basically I want a PR being merged: https://github.com/boostorg/iostreams/pull/25 This patch and some others looks good to me. It fixes a quite annoying warning. Can anybody with permission merge it?

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[Coroutine] What happened to WINFIBERS?
by Tobias Loew 12 Apr '16

12 Apr '16

When testing 1.61 beta I couldn't find any reference to BOOST_USE_WINFIBERS in the sources and also the WinFibers implementation-file "execution_context_winfib.ipp" was missing. Has support for windos-fibers been removed? Tobias -- View this message in context: http://boost.2283326.n4.nabble.com/Coroutine-What-happened-to-WINFIBERS-tp4… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Compiling boost_thread on CentOS 7 32 bit system
by Kristian 11 Apr '16

11 Apr '16

Hi, I am trying to build boost 1.60 on a CentOS 7 32 bit system. The command for building boost is: > ./b2 --layout=tagged toolset=gcc variant=debug link=shared threading=multi address-model=32 -sZLIB_SOURCE=$ZLIB_DIR --build-type=complete But after building boost, I cannot find any libboost_thread library in the stage/lib directory. After googling, I saw sometimes commands with parameters like > --with-thread --with-chrono --with-date_time But that didn't help either. After the second try, I only saw these files: > libboost_chrono-mt-d.so > libboost_chrono-mt-d.so.1.60.0 > libboost_chrono-mt.so > libboost_chrono-mt.so.1.60.0 > libboost_system-mt-d.so > libboost_system-mt-d.so.1.60.0 > libboost_system-mt.so > libboost_system-mt.so.1.60.0 Can someone tell me, what I am missing here?

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[Nowide] Review Manager Needed
by Artyom Beilis 11 Apr '16

11 Apr '16

Boost.Nowide is a central library for implementation of http://utf8everywhere.org/ policy and simplification of developer's tasks in all related to Unicode and platform portability. http://cppcms.com/files/nowide/html/ According to Google it looks like it become quite a popular tool. It still looks for a review manager. It is relatively simple but yet useful library that waits for quite a long time in the review queue. Volunteer for review manager is needed. Artyom Beilis

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[iostreams] basic_array_source: improper constructor argument
by Tatsuyuki Ishi 08 Apr '16

08 Apr '16

Since this is a 1-minute fix, I won't open any tickets: template<int N> basic_array_source(char_type (&)[N]); -> template<int N> basic_array_source(const char_type (&)[N]); Since iostream sources are read-only, this should be const.

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[Root Pointer] Seeking a Review Manager
by Phil Bouchard 08 Apr '16

08 Apr '16

Greetings, - "Root Pointer" is an alternative to the long unsolved problem of garbage collectors which lasted for more than 70 years! - Thanks to Paul A. Bristow for his help on the generation of the documentation which is now available at the following link: http://philippeb8.github.io/root_ptr/ (I apologize for the misplaced images in the rationale) - The library itself can be found here: https://github.com/philippeb8/root_ptr/ All examples and tests compile fine with BJAM with GCC and MSVC. - Also here is a quick overview on the benchmarks: Single threaded: unique_ptr (new): 43.2705 unique_ptr (make_unique): 42.4111 shared_ptr (new): 68.9101 shared_ptr (make_shared): 46.6575 shared_ptr (allocate_shared_noinit): 31.2334 root_ptr (new): 30.3701 Multi threaded: unique_ptr (new): 42.1397 unique_ptr (make_unique): 43.4631 shared_ptr (new): 76.4543 shared_ptr (make_shared): 76.6611 shared_ptr (allocate_shared_noinit): 81.9926 root_ptr (new): 66.3417 - An example of its usage can be seen here: https://github.com/philippeb8/root_ptr/blob/master/example/t100_test1.cpp We can see in the aforementioned link that outputting part of a complex graph, cyclic or not, can be done in the following simple way: cout << "Mind dump:" << endl; cout << * t100 << endl; cout << "Searching for: \"einstein\"" << endl; if (node_ptr<neuron_base> p = t100->search("einstein")) cout << p->sort().unique() << endl; cout << "Searching for: \"graviton\"" << endl; if (node_ptr<neuron_base> p = t100->search("graviton")) cout << p->sort().unique() << endl; Sincerely yours, -Phil

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[clang][preprocessor] Testing of clang emualting the VC++ preprocessor on Windows
by Edward Diener 07 Apr '16

07 Apr '16

I have made local changes in the Boost preprocessor config.hpp on the 'develop' branch to have clang's emulation of the non-standard VC++ preprocessor act like the VC++ preprocessor as far as Boost PP is concerned. Boost PP has a large number of workarounds for VC++ without which Boost PP preprocessor code would not work when compiling using any version of VC++. I have tested the usual compilers extensively to make sure they are unaffected by these changes as well as the normal clang-linux implementation. Everything remains the same for these compilers with my changes so I am assured the changes will not affect any other compiler implementation. I was able to test both clang-3.8 and the latest build of clang, which is clang-3.9, by invoking clang-cl. My user-config.jam file for these entries looks like: using clang-win : 3.8 : SomePath/clang-cl : <compatibility>vc12 using clang-win : 3.9 : SomePath/clang-cl : <compatibility>vc14 By passing toolset=clang-win-3.8 or toolset=clang-win-3.9 I was able to successfully test these implementations against the Boost PP test code. There are quite a few failures in this clang emulation of the VC++ preprocessor when tested against the preprocessor test code. In fact testing clang emulation of VC++ preprocessor when I don't treat clang as VC++ in Boost PP, but as its normal C++ standard conforming preprocessor, still fails a few cases but far less than when clang is treated as VC++ in Boost PP. Needless to say when invoking clang-linux, which tests the normal clang implementation whether on Windows or Linux, there are no failures in the Boost PP tests. I am perfectly willing to push my changes to 'develop' for the preprocessor. The changes are essentially just in the Boost PP config.hpp file, which sets macros which control the compiler workarounds in Boost PP. As I have previously stated I am not personally willing to try to figure out or report to clang why their VC++ preprocessor emulation in Boost PP is failing, but others who are interested can do so if they wish. My personal reasons for this is that I think it is a very bad thing to attempt to replicate an already flawed C++ preprocessor in another compiler in general code. I also have spent enough time working with the VC++ preprocessor trying to find workarounds for its non-standard behavior that I do not want to do so for another preprocessor which attempts to be non-standard. I posted this to alert others to my plans to update Boost PP on 'develop' with this change, in case anybody is greatly opposed to it or wants to discuss it further. The change will not affect any other compiler but clang in VC++ preprocessor emulation mode. Unless I hear objections etc. I plan to push my update within the next day although I will wait awhile for any replies to this post.

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New libraries are missing in library list
by Antony Polukhin 07 Apr '16

07 Apr '16

Hi, Seems that new libraries (Compute, DLL, Hana, Metaparse) are not available from pages http://www.boost.org/doc/libs/1_61_0_b1/ and http://www.boost.org/doc/libs/1_61_0/. Please, could someone fix that? -- Best regards, Antony Polukhin

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Nasty compile time reflection and iteration for POD types using C++14 without macro
by Antony Polukhin 07 Apr '16

07 Apr '16

Hello, I've come up with a trick that may be useful in Boost.Hana, Boost.Serialization or some other libraries. Here's a small motivating example: #include <cstdio> #include <boost/type_index.hpp> #include "magic.hpp" struct foo { unsigned char i0; unsigned int i1; unsigned short i2; unsigned long long i3; unsigned char ar[2]; int q; std::size_t w; int* p1; const void* p2; int const**const**** p_crazy; const double d; }; template <std::size_t I, class T> void print(T& f) { printf( "%lu\t\t%s\n", (std::size_t)get(f), boost::typeindex::type_id<decltype(get(f))>().pretty_name().c_str() ); } int main() { foo f {10, 11, 12, 13, {14, 15}, 16, 17, 0, 0, 0, 30.0}; print<0>(f); print<1>(f); print<2>(f); print<3>(f); print<4>(f); print<5>(f); print<6>(f); print<7>(f); print<8>(f); print<9>(f); print<10>(f); print<11>(f); static_assert(tuple_size<foo>() == 12, "failed tuple size check"); } That example will output: 10 unsigned char 11 unsigned int 12 unsigned short 13 unsigned long long 14 unsigned char 15 unsigned char 16 int 17 unsigned long 0 int* 0 void const* 0 int const** const**** 30 double Core ideas: 1) We may detect the POD structure fields by the POD's constructor: template <std::size_t I> struct ubiq { std::size_t* ref_; template <class Type> constexpr operator Type() const noexcept { ref_[I] = type_to_id(identity<Type>{}); return Type{}; } }; template <class T, std::size_t... I> constexpr auto type_to_array_of_type_ids(std::size_t* types) noexcept -> decltype(T{ ubiq{types}... }) { return T{ ubiq{types}... }; } Here type_to_array_of_type_ids will return array with types via `types`, each element of array encodes some basic type. 2) Then we convert that array into an std::index_sequence<I...> and create a type with same layout as our POD type: template <std::size_t... I> constexpr auto as_tuple_impl(std::index_sequence<I...>) noexcept { return std::tuple< decltype( id_to_type(std::integral_constant<std::size_t, I>{}) )... >{}; } 3) Now we have a type with same layout, and we cast the structure to that type: template <std::size_t I, class T> decltype(auto) get(const T& val) noexcept { auto t = reinterpret_cast<const decltype(detail::as_tuple<T>())*>( std::addressof(val) ); return get(*t); } Drawbacks: * works for POD types only (could be possibly extended to trivial constructible type) * structures with non-default alignment are not supported * step 3) contains an UB, but even without that step we're still able to get field types of the POD type and fields count * current draft implementation does no support nested PODs (could be fixed easily) * current draft implementation works only on libc++ (could be fixed easily, requires reimplementing std::tuple) * there's no known to me way to make get<>() method constexpr * does not detect constness (because of that get<>() always returns const reference) Is there any interest in this feature? Sources https://github.com/apolukhin/magic_get/blob/master/magic2.cpp Online experiments can be done here: http://coliru.stacked-crooked.com/a/c33857e566e76ce2 -- Best regards, Antony Polukhin

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Boost 1.61.0 Beta 1
by Vladimir Prus 06 Apr '16

06 Apr '16

The first beta packages for 1.61.0 beta 1 are now available: http://boost.cowic.de/rc/boost_1_61_0_b1.zip http://boost.cowic.de/rc/boost_1_61_0_b1.7z http://boost.cowic.de/rc/boost_1_61_0_b1.tar.bz2 http://boost.cowic.de/rc/boost_1_61_0_b1.tar.gz There are no changes compared to RC2, expect for different names of the archives and different name of the top-level directory in the archives. The SHA256 checksums are as follows: 3f8888099ee6f62b412a13be916dead2bacbdd6d69e5afd5b6fea4bb738e5df4 boost_1_61_0_b1.7z 866941f0038b27fcc69ced1490b2dc5fa8d20f505d66b939a92a68ef194d1a6c boost_1_61_0_b1.tar.bz2 0b92c5fb5b91641409b9675b2fd11d3b3fa5f71dd986d3b5fb03da201bf55474 boost_1_61_0_b1.tar.gz 9dffe5ee7f5f7bf7695f5738c686e44bd266933e3ca68732b0de5520c3c82615 boost_1_61_0_b1.zip Signed list of checksums should be posted within 24 hours. As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. It was discovered that the .zip and .7z archives actually have LF line endings, at least in some places. Fixing this is not quite trivial, as Travis uses ancient version of Ubuntu and Git, and is not deemed critical, as most Windows editors handle LF just fine. We might do something for the final release, or might not. Thanks! -- The release managers

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[endian] Project not maintained
by Tatsuyuki Ishi 06 Apr '16

06 Apr '16

The endian library was going to support float in 1.58, but even 1.61 is going to release soon, there is no news about the feature. I'm not going to say, that this library should have been rejected, but since it's accepted, the maintainer should at least complete the work. And what's the situation now? The float point feature is overdue for 1 year. The project is almost like abandoned. Last commit 4 months ago. Even the library isn't completed. I hope the creator, Beman, to take responsibility about this library.

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[multiprecision][build] Massive unexplained failures in develop
by John Maddock 04 Apr '16

04 Apr '16

Can anyone help me understand why just about every multiprecision test on every platform is failing with link errors, for example: http://www.boost.org/development/tests/develop/developer/output/teeks99-09d… Note that it's complaining about a missing *object* file: I've checked, and the necessary source files are present in the repository, plus I've pulled those changes on to a virtual machine and everything builds fine locally. So there's something odd about the build when run from /status or what exactly? I'm hoping someone can spot something obvious here, or else the testers can tell me where the object file actually placed? Thanks, John.

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[build] How to use with clang on windows?
by John Maddock 03 Apr '16

03 Apr '16

What's the correct way to configure clang on windows with current Boost.Build? If I use: using clang-win : 3.7 : "C:/Progra~2/MICROS~4.0/VC/Clang 3.7/bin/x86/clang.exe" : <cxxflags>-std=c++11 <compatibility>vc14 ; to configure the clang that ships with VC14 I see: compile-c-c++ ..\..\..\bin.v2\libs\smart_ptr\test\shared_ptr_basic_test.test\clang-vc14-win-3.7\debug\shared_ptr_basic_test.obj clang.exe: error: no such file or directory: '/Od' clang.exe: error: no such file or directory: '/Ob0' clang.exe: error: no such file or directory: '/W3' clang.exe: error: no such file or directory: '/GR' clang.exe: error: no such file or directory: '/MDd' clang.exe: error: no such file or directory: '/Zc:forScope' clang.exe: error: no such file or directory: '/Zc:wchar_t' clang.exe: error: no such file or directory: '/wd4675' clang.exe: error: no such file or directory: '/EHs' Same errors with the llvm clang-3.9. On the other hand if I initialize with: using clang : : "C:/Progra~2/LLVM/bin/clang.exe" : <cxxflags>-std=c++14 <compatibility>vc14 <cxxflags>-fms-compatibility-version=19.00.22609 ; Then this sort of works for llvm clang, but not the msvc one (can't find c2.exe), but the compiler is identified as "clang-linux" and I see: LINK : warning LNK4044: unrecognized option '/-start-group'; ignored LINK : warning LNK4044: unrecognized option '/Bstatic'; ignored LINK : warning LNK4044: unrecognized option '/Bdynamic'; ignored LINK : warning LNK4044: unrecognized option '/-end-group'; ignored Plus some linker errors such as: yield_k_test.obj : error LNK2019: unresolved external symbol __mm_pause referenced in function "void __cdecl boost::detail::yield(unsigned int)" (?yield@detail@boost@@YAXI@Z) Ideas? Thanks, John.

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Boost 1.61.0 open for fixes
by Vladimir Prus 02 Apr '16

02 Apr '16

The master branch is now open for bugfixes for 1.61.0. Please make sure that develop tests are healthy prior to merging. We're two weeks late relative to the plan, so further dates were also moved by two weeks in the calendar. -- The release managers

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[Trac][convert] Associate Vladimir as author of Boost.Convert
by Vicente J. Botet Escriba 01 Apr '16

01 Apr '16

Hi, I requested sometime ago to add convert to the Trac system. It was done, but it was associated to me as maintainer. Please, could someone assign it to Vladimir Batov Vladimir, I guess you need to give your use in name. Best, Vicente Convert <http://www.boost.org/doc/libs/1_60_0/libs/convert/> An extendible and configurable type-conversion framework. Author(s) Vladimir Batov First Release 1.59.0

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Coroutine2 examples - Cannot link properly.
by Carlos Ferreira 01 Apr '16

01 Apr '16

Hello to all. I'm having trouble in compiling the coroutine2 examples. For the fibonacci example, the following linking error occurs: /usr/include/boost/coroutine2/detail/pull_control_block.ipp:62: undefined reference to `boost::context::execution_context::current()' Now, I know that I have to link against boost context, something that I'm already doing, but for some reason, it is not enough. Can anyone help me with this? Thank you. -- Carlos Miguel Ferreira Researcher at Telecommunications Institute Aveiro - Portugal Work E-mail - cmf(a)av.it.pt Skype & GTalk -> carlosmf.pt(a)gmail.com LinkedIn -> http://www.linkedin.com/in/carlosmferreira

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[boost 1.61] authorization to merge to master
by Raffi Enficiaud 31 Mar '16

31 Mar '16

Dear Boost, I would like to merge a boost.test bugfix to master. Those changes are running on develop for a week. I haven't done my PR for the website change log update because of that (would change the content of the PR). According to the schedule, boost 1.61 is open for bugfixes since 10 days now, but as I understood, we are still waiting for post RC2 go. - do I still have time for the website PR? - would the opening 1.61 for bugfixes be announced on the ML? - Am I allowed to merge those changes, so that I can reopen develop for post 1.61 developments? Thanks, Raffi Enficiaud

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